How severe is CVE-2011-4278?

No CVSS score has been assigned to CVE-2011-4278 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2011-4278?

CVE-2011-4278 affects the following packages: moodle/moodle (Packagist), moodle/moodle (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2011-4278?

Update moodle/moodle to 1.9.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2011-4278 is resolved across your whole dependency graph.

How do I detect CVE-2011-4278 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for moodle/moodle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2011-4278 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2011-4278 actively exploited in the wild?

No public exploit code has been indexed for CVE-2011-4278 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2011-4278?

CVE-2011-4278 has an EPSS (Exploit Prediction Scoring System) score of 1.8%, placing it in the 79th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2011-4278?

CVE-2011-4278 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2011-4278 published, and has it been updated?

CVE-2011-4278 was published on May 13, 2022 and was last updated on January 17, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2011-4278 — moodle

Fix: moodle/moodle@34b93e3

CVE-2011-4278 is a Cross-site Scripting (XSS) vulnerability in moodle/moodle. A fix is available for moodle/moodle — see the affected versions and patch details below.

Moodle XSS In Tag Autocomplete functionality

Published

May 13, 2022

Updated

Jan 17, 2024

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs79th percentile — riskier than 79% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

🐘moodle/moodle🐘moodle/moodle

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Cross-site scripting (XSS) vulnerability in the tag autocomplete functionality in Moodle 1.9.x before 1.9.11 and 2.0.x before 2.0.2 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`moodle/moodle`	all versions	1.9.11`composer require moodle/moodle:^1.9.11`
🐘Packagist	`moodle/moodle`	≥ 2.0&&< 2.0.2	2.0.2`composer require moodle/moodle:^2.0.2`

Affected Products

1 product · 12 configurations

Application

moodlemoodle

12 versions

1.9.11.9.21.9.31.9.41.9.51.9.61.9.71.9.81.9.91.9.102.0.02.0.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for moodle/moodle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update moodle/moodle to 1.9.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2011-4278 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2011-4278 in your dependencies?

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